WO2007122079A1

WO2007122079A1 - Combined fastening arrangement with coating

Info

Publication number: WO2007122079A1
Application number: PCT/EP2007/053227
Authority: WO
Inventors: Manfred Hofschneider
Original assignee: Abc Umformtechnik Gmbh & Co. Kg
Priority date: 2006-04-24
Filing date: 2007-04-03
Publication date: 2007-11-01
Also published as: EP1899171B1; ATE423689T1; DE112007000427A5; DE502007000465D1; EP1899171A1; ES2319467T3; DE202006008314U1

Abstract

The present invention relates to a combined fastening arrangement having a head part (1) for torque application and having a shaft part (2) which has a threaded section (3) at the free end. A disk (4) is rotatably held on the head part (1) and on the shaft part (2). The head part (1) and the disk (4) are covered with a coating (B1, B2). The head part (1) is covered with a first functional coating (B1), and the disk (4) is covered with a second functional coating (B2) which differs from the first functional coating (B1), in such a way that, during tightening, the disk (4) does not perform a relative movement with respect to a component (W) to which a connection is to take place, that is to say that, during tightening, the head part (1) always rotates on the disk (4), but not the disk (4) on the component (W).

Description

"Combined mounting arrangement with coating"

The invention relates to a combined mounting assembly with a head portion for torque application and with a shaft portion having a Gewi ndeabschnitt at the free end, wherein on the head part and on the shaft portion a disc is rotatably supported and wherein the head part and the disc are coated with a coating ,

In a specific embodiment, this can be a combined fastening arrangement in which the head part is formed by a torque application head and the shaft part is formed by a shaft, which together form a screw body having the threaded portion at its free end, between the head and the threaded portion on the shaft, the disc is rotatably held.

Thus, preferably, the mounting arrangement may be formed as a combined fastener with a head for torque application and with a shaft having a threaded portion at the free end, wherein the head and the shaft form a screw body, wherein between the head and the threaded portion on the Shaft a disc is rotatably and captively held and wherein the head, the shaft and the disc are coated with a coating.

Such fasteners are known from the German utility model DE 296 14 320 U1 and DE 298 19 782 U1. These known fastening elements have in a preferred use as wheel bolts the advantage that each held captive on the shaft disk, in particular when they are in an investment area for a vehicle wheel tapers spherical or conical, ensures a defined attachment of the vehicle wheel to the vehicle hub. In DE 298 19 782 U1 while a special technical design of the holder of the disc is described on the shaft, which has proven in terms of their cheap manufacturability in practice. An advantage consists in addition to an increase in the compliance of the entire compound by an enlarged clamping length in a relation to one-piece fasteners more stable torque-biasing force behavior.

It is also mentioned in DE 298 19 782 U1 that both the screw body, that is to say the head and the shank, and the disk on its surface are provided with a corrosion-reducing zinc-containing and / or nickel-containing protective layer, in particular with a multiple coating, can be covered. It is also mentioned that such a functional coating can serve to protect against damage and / or reduce corrosion and can also be tribotechnical and / or coloring.

The invention is based on the object to provide a combined mounting arrangement, in particular in a design as a combined fastener of the type mentioned, for which the tightening is independent of the material of the part with which the connection should be made. Such a component can, for. Example, be a wheel whose rim consists of a coated with a cathodic dip alloy steel or aluminum. Here, a long-term stable damage-free connection is to be achieved.

The object of the invention is achieved in that the head part is coated with a first functional coating and the disk with a second functional coating different from the first functional coating in such a way that when tightened the disk is opposite a component with which a connection is to be made. no relative movement executes, ie that when tightening always the head part rotates on the disc, but not the disc on the component. According to the invention, in this way, in addition to the achievement of corrosion protection, the properties of the various pairings of surfaces occurring, namely the mating of the surface of the head portion with the surface of the disc, from the surface of the disc with the surface of the component with which the connection is to take place , as well as possibly also from the surface of the shaft part, in particular the thread of the shaft part, with the, in particular in a screw-in, surface of the component with which the connection is to be made, are matched to each other in an optimal manner. In particular, in each case a desired tribological behavior of said pairings can be set and coordinated with each other. So it is advantageously z. Example, on the one hand the risk of an automatic release of the connection of the fastening arrangement according to the invention with a component, such as a vehicle to counteract under dynamic load, on the other hand, but also to achieve, for example, that the mounting arrangement according to the invention in the so-called abuse case, ie when tightening with particularly high torques, not already at comparatively small tightening torques by plasticizing or in extreme cases by demolition failed.

Further advantageous features of the invention are contained in the subclaims and the following description.

Reference to a preferred embodiment shown in the drawing, the invention will be explained in more detail below. Showing:

1 is a sectional view of a disc of a fastening arrangement according to the invention, which is designed as a fastener according to the invention,

2 is a perspective view of the disk shown in Fig. 1 on a reduced scale,

3 shows a partially cutaway view of a screw element formed from a head as a head part and a shaft as a shaft part of a fastening element according to the invention, 4 is a perspective view of the screw body shown in Fig. 3 on a reduced scale,

Fig. 5 is an illustration of the fastening arrangement according to the invention in

Front View,

6 is a perspective view of the mounting arrangement according to the invention shown in Fig. 5 on a reduced scale,

7 shows a cross section through a first functional coating of a fastening arrangement according to the invention,

8 shows a cross section through a second functional coating of a fastening arrangement according to the invention,

9 shows a cross section through a fastening arrangement according to the invention in the assembled state.

In the various figures of the drawing, the same parts are also provided with the same reference numerals, so that they are usually described only once in each case.

As the illustrations in FIGS. 1 to 6 show, a fastening element according to the invention has a head part 1 designed as a head 1 for torque application and a shaft part 2 designed as a shaft 2, which in turn has a threaded section 3 at its free end. Head 1 and shaft 2 together form a screw body S, which is shown in Fig. 3 and 4 as a single part. The thread of the threaded portion 3 may be primarily a rolled thread, wherein the diameter D _{G of} the threaded portion 3 is greater than the diameter Ds of the shaft 2, as shown in FIG. The thread of the threaded portion 3 can be made with advantage, before the disc 4 is connected to the consisting of head 1 and shaft 2 screw body S. As shown in FIGS. 5 and 6, a disc 4 is rotatably held between the head 1 and the threaded portion 3, which is shown in Fig. 1 and 2 as a single part. The disk 4 is held between the head 1 and the threaded portion 3 at a located on the shaft 2 edge 5, the outer diameter D _{R is} greater than the diameter D _{s of} the shaft 2, as also Fig. 3 shows. For the rotatable support of the screw body S is guided with its shaft 2 through an annular opening 6 in the disc 4, whose diameter D _{0 is} smaller than the outer diameter D _{R of} the edge 5, but larger than the diameter Ds of the shaft second

Both the screw S and the disc 4 may, for example, a tempered, d. H. z. As a hardened and annealed, tempered steel exist. The head 1, the shaft 2 and the disc 4 are coated on their respective surfaces, which is illustrated by the surface areas indicated by the reference symbols B1 and B2 in FIGS. 1, 3 and 5.

According to the invention, it is now provided that the head part 1, in the special case the head 1, and preferably also the shaft part 2, in the special case the shaft 2, with a first functional coating B1 and the disc 4 with one of the first functional coating B1 second functional coating B2 are coated.

The first coating B1 and / or the second coating B2 may comprise at least one corrosion-reducing, in particular zinc-containing protective layer. In addition, the first coating B1 and / or the second coating B2 can comprise at least one tribotechnically active layer, in particular a friction-reducing sliding layer.

On the one hand, it is possible here for the corrosion-reducing protective layer and the tribotechnically active layer to be identical, but it can also preferably be provided that the first coating B1 and / or the second coating B2 each consist of a layer system with two or more individual layers S1, S2 , S3, S4 are formed, wherein the individual layers S1, S2, S3, S4 each separately take over the corresponding functions, but can also penetrate each other at least partially. Examples of coatings B1, B2 of the latter type are shown in FIGS. 7 and 8, wherein FIG. 7 is representative of a preferred first functional coating B1 and FIG. 8 for a preferred second functional coating B2 of a fastening arrangement according to the invention.

As FIGS. 7 and 8 show, both the first coating B1 of the head part 1, in the illustrated case of the screw body S, of a layer system with two individual layers S1, S2 and the second coating B2 of the disk 4 are made of a layer system with two individual layers S3 , S4, wherein the individual layers S1, S2, S3, S4 are each assigned specific functions. Both the two individual layers S1, S2 of the first coating B1, as well as the two individual layers S3, S4 of the second coating B2 partially penetrate each other, which can be achieved by the corresponding production technology and compatibility - or preferably by an affinity - of the layer constituents , This advantageously results in a firmer and more compact layer composite with increased resistance to environmental influences.

The respective lower individual layers S2, S4 are preferably base layers which serve to achieve cathodic corrosion protection. The cathodic corrosion protection is an electrochemical protection method in which the electrolyte, such as. As water, a direct electrical current flows to the metal structures to be protected. Due to this protective current, a cathodic polarization takes place on the metal surface in the electrolyte. This prevents metal ions from being released from the metal surface. For the generation of the protection current, for example, galvanic active anodes, so-called sacrificial anodes, find use, based on the utilization of the voltage difference between a lower noble anode material and the object to be protected, eg. As steel, based. The respective lower individual layers S2, S4 can therefore consist in particular of such a base anode material, such as magnesium or zinc.

In a particularly preferred manner, the respective lower individual layers S2, S4 may consist of a combination of zinc and aluminum lamellae which are in an inorganic or at least almost completely inorganic, in particular on the basis embedded silica matrix are embedded. The application can be done by cold dipping in an aqueous solution or by spraying with subsequent burning. In addition to an alkali hydroxide, the solution may also contain an organic substance, such as a copolymer based on polypropylene glycol and polyethylene glycol, a silicone polymer, or a quaternary ammonium compound, preferably in proportions of from 0.01 to 1%.

In a dipping / spinning process for drum products, which is particularly suitable for small parts, they are immersed in the layer-forming bath after cleaning, after which the superfluous solution is spun off. The wet parts are first oven dried and then heated to the temperature of preferably about 300 ^° C. to form the coating. The method makes it possible to completely wet the surface of the parts, so that the inner sides of pipes or cavities, in the present case, the annular opening 6 of the disc 4, are coated.

For bulk material, the spraying method is particularly suitable, in which, after the cleaning, the small parts for applying the solution are introduced into a special spraying system. Thereafter, the heat treatment is carried out in the same way as in the immersion / centrifuging process.

Both methods are basically suitable for producing a fastening arrangement according to the invention, such as a fastening element according to the invention, the second representing the gentler procedure.

In such a structure of the layers S2, S4, the corrosion resistance is dependent on the respective layer thickness D2, D4. For example, given a specific weight of the individual layers S2, S4 of more than 24 g / m ² , ie at an average layer thickness D2, D4 of about 5 to 8 microns, in the salt spray test according to DIN 50 021 values of about 600 hours and at a specific weight of more than 36 g / m ² , ie at an average layer thickness D2, D4 of about 8 to 10 microns, values of about 1000 hours can be achieved. The corrosion resistance in the salt spray test is not affected at a heat storage of 100 hours at 180 ⁰ C. The corrosion resistance results from a synergistic combination of several factors, namely first a barrier effect, which is caused by the lamellar structure of the layers S2, S4, second, a controlled cathodic protection due to an adjustable ratio of zinc to the iron-containing body, in the present case the Head 1, the shaft 2 and the disc 4, and thirdly, the slowing down of natural zinc and aluminum consumption by the passivation of the layers S2, S4 by means of the inorganic matrix.

The mentioned, particularly preferred layer structure of the individual layers S2, S4 furthermore has a number of advantages which predestine it for the use of wheel bolts in automobiles. As a result of the non-electrolytic application of the coating no hydrogen embrittlement. Resistance to automotive fuels, such as standard fuels, diesel, engine oil, organic solvents, coolant, brake fluids, etc., in accordance with VDA 621-412 is satisfactory, resulting in e.g. B. expresses that after a 24-hour immersion in brake fluid at 20 ⁰ C, the coating is not affected. The layers S2, S4, which are of an aluminum gray color, retain their structural properties at room temperature up to a temperature of about 300 ^° C., ie up to the formation temperature of the coating, and have ductility sufficient for joint elastic deformation with steels. In addition, the individual layers S2, S4 advantageously contain no heavy metals, such as lead, cadmium, nickel, chromium or mercury, and thus meet the highest requirements in terms of health and environmental protection and safety.

The respective upper individual layers S1, S3 may preferably be covering or sealing layers which further increase the resistance to corrosion, for example to contact corrosion when paired with magnesium, aluminum, rubber, etc., and protection against mechanical damage. The application can be carried out in particular with layer thicknesses D1, D3 of less than 5 .mu.m, preferably of only up to 1 .mu.m, in a dipping / spinning or in a dipping / draining process. The parts to be coated, ie the head part 1, in particular the screw body S, and the disc 4, are brought into an inorganic aqueous solution, which leads to the formation of a reactive coating. The coating present after drying can in particular consist of sodium, potassium and / or lithium Silicate exist and is transparent in this case, so that he z. B. aluminum gray coloration of an underlying zinc-aluminum lamellar layer is not affected.

The respective upper individual layers S1, S3 can advantageously be modified in the sense of setting certain tribotechnical characteristics, in particular in the case where a lubricating effect, ie a reduction in the coefficient of friction in one of the abovementioned pairings, such as "surface head part 1" with "surface Disc 4 "," surface disc 4 "with" surface component "and / or" surface shaft 2 ", in particular" surface thread 3 "with" surface "component", is desired.

The mentioned friction pairings are shown by way of example in FIG. 9. The pairing "surface head part 1" with "surface disc 4" is here by the reference P1, the pairing "surface disc 4" with "surface component" by the reference P2 and the pairing "surface thread 3", with "surface" component The component itself, which is preferably a wheel hub and may also be designed in several parts, is designated by the reference symbol W.

It can be adjusted either on the screw body S, as well as on the disc 4, a lubricating effect, or it is lubricated only a part, preferably the screw body S, in order to achieve that the disc 4 when tightening the fastener according to the invention against a wheel no or executes only a very small relative movement, that is, the screw body S rotates on the disc 4 and not the disc 4 on the component. The friction coefficient in the pairing P1 "surface head part 1" with "surface slice 4" is smaller than the static friction coefficient in the pairing P2 "surface slice 4" with "surface component".

The modification can be carried out by introducing into the layers S1, S3 dry lubricants, for example polytetrafluoroethylene, polyethylene, polyethylene glycol, paraffin, molybdenum-containing substances, such as molybdenum sulfide or oxide, and graphite, in finely dispersed, preferably colloidally distributed, form. Due to the nature of the lubricant and the amount of lubricant content, the friction coefficients in the mentioned pairings can be set within wide limits. A preferred lubricant content is in the range of up to about 15%, more preferably from about 5 to 15%.

The coatings B1, B2 formed from the upper individual layers S1, S3 and the lower individual layers S2, S4 can advantageously have overall thicknesses DB1, DB2 of approximately 5 to 15 μm, with the individual layers S1 / S2, S3 / S4 being up to half the value their respective thickness D1, D2, D3, D4 can penetrate.

Special embodiment

In a combined fastening element according to the invention, sublayers S2, S4, which consisted of a combination of zinc and aluminum fins, were initially formed on the surface of both the screw body S and the disk 4 for cathodic corrosion protection in the manner described above in a dip / spin method. which were embedded in an inorganic matrix. Sublayers S2, S4 contained about 71.5% metallic zinc, about 7.3% metallic aluminum and about 18.8% SiO2.

On the surface of the sub-layer S2 of the screw S was in addition to further increase the corrosion protection and to set a desired coefficient of friction in the manner, as stated above, applied a further - silicate - sub-layer S1 containing polytetrafluoroethylene as a lubricant additive. The resulting coating B1 had a total thickness of about 10 microns and contained about 50.2% metallic zinc, about 7.0% metallic aluminum, about 15.0% SiO 2, about 0.6% PTFE and about 11.0% sodium silicate , The salt spray resistance according to DIN 50021 was more than 720 hours without formation of red rust. A friction coefficient determined in accordance with DIN 946 ranged from 0.09 to 0.14.

On the surface of the sub-layer S4 of the disc 4, in addition to further increasing the corrosion protection in the manner set forth above, a further silicate sub-layer S3 was applied, which was free of lubricant, but otherwise had the same composition as that on the sub-layer S2 applied additional layer S1. The resulting coating B2 had a total thickness of about 10 microns. The salt spray resistance according to DIN 50021 was more than 720 hours without formation of red rust. A friction coefficient determined according to DIN 946 was in the range of more than 0.15.

With the combined fastening element according to the invention, it was possible to ensure, particularly in the case of KTL-coated steel wheels, that the disk 4 did not turn against the wheel cap W when it was being tightened.

The invention is not limited to the embodiment described, but also includes all the same in the context of the invention embodiments. Thus, the structural design of the combined fastener element according to the invention of the illustrated example, for example, deviate so that it has all the features as described in the aforementioned utility model DE 298 19 782 U1. The compositions of the coatings B1, B2 can vary widely, wherein the coatings B1, B2 do not necessarily have to be formed from the described partial layers S1, S2, S3, S4.

It is also within the scope of the invention, when the head part 1 is formed of a nut and the shaft part 2 of a separate shaft, wherein the shaft with an end which is opposite to the threaded portion 3 bearing free end, with the component W form -, non-positively and / or cohesively connectable.

In addition, further expedient technical measures may be provided, such as the setting of certain roughness values of the coatings B1, B2, whereby an increase in the coefficient of friction can be brought about if necessary and / or an existing difference in the friction coefficient of the coatings B1, B2 can be increased.

Furthermore, the invention is not limited to the feature combination defined in claim 1, but may also be defined by any other combination of certain features of all individually disclosed features. This means that in principle virtually every individual feature of claim 1 can be omitted or replaced by at least one individual feature disclosed elsewhere in the application. In this respect, the claim 1 is to be understood only as a first formulation attempt for an invention. reference numeral

1 head

2 shaft

3 threaded section of 2

4 disc

5 edge to 2

6 ring opening of 4

B1 first functional coating (on S)

B2 second functional coating (on 4)

DG outer diameter of 3

DR outer diameter of 5

Ds diameter of 2

D ₀ inner diameter of 6

D1 Thickness of S1

D2 thickness of S2

D3 thickness of S3

D4 thickness of S4

DB1 thickness of B1

DB2 thickness of B2

P1 friction pair 1/4

P2 friction pair 4 / W

P3 friction pair 3 / W

S screw body from 1 and 2

S1 upper sublayer of B1

S2 lower sub-layer of B1

S3 upper part of B2

S4 lower sub-layer of B2

W component

Claims

claims

1. Combined mounting arrangement with a head part (1) for torque application and with a shaft part (2) having a threaded portion (3) at the free end, wherein on the head part (1) and on the shaft part (2) has a disc (4) is held rotatably and wherein the head part (1) and the disc (4) are coated with a coating (B1, B2), characterized in that the head part (1) with a first functional coating (B1) and the disc (4) are coated with a second functional coating (B2) distinguished from the first functional coating (B1) in such a way that, when tightened, the disk (4) does not move relative to a component (W) with which a connection is to take place, d. h. That when tightening always the head part (1) on the disc (4) rotates, but not the disc (4) on the component (W).

2. Fastening arrangement according to claim 1, characterized in that the first coating (B1) and / or the second coating (B2) comprises at least one corrosion-reducing, in particular zinc-containing, protective layer (S2, S4).

3. Fastening arrangement according to claim 2, characterized in that the corrosion-reducing, in particular zinc-containing protective layer (S2, S4) consists of a combination of zinc and aluminum fins, which are produced in an inorganic, in particular based on silica, Embedded matrix.

4. Fastening arrangement according to claim 2 or 3, dadu rc hgekennzeichnet that the corrosion-reducing effective layer (S2, S4) has a thickness (D2, D4) of 5 to 10 microns.

5. Fastening arrangement according to one of claims 1 to 4, dadu rch ge cen ze ze ch n et, that the first coating (B1) and / or the second coating (B2) at least one tribotechnically effective layer (S1, S3), in particular a friction-reducing sliding layer comprises.

6. Fastening arrangement according to claim 5, characterized in that the tribotechnically active layer (S1, S3) is prepared on the basis of sodium, potassium and / or lithium silicate.

7. Fastening arrangement according to claim 5 or 6, dadu rch ge ke nn ze zen et that the tribotechnically active layer (S1, S3) as a friction-reducing sliding layer dry lubricants such as polytetrafluoroethylene, polyethylene, polyethylene glycol, paraffin, graphite or molybdenum-containing substances such as molybdenum sulfide or oxide, with a preferred lubricant content in the range of up to about 15%.

8. Fastening arrangement according to one of claims 5 to 7, characterized in that the tribotechnically active layer (S1, S3) has a thickness (D1, D3) of 5 to 10 microns.

9. Fastening arrangement according to one of claims 1 to 8, dadu rch GE n ze ze ch n et, that the first coating (B1) and / or the second coating (B2) each consist of a layer system with two or more individual layers (S1, S2, S3, S4) are formed.

10. Fastening arrangement according to one of claims 1 to 9, characterized in that in a layer system of the first coating (B1) and / or the second coating (B2) with two or more individual layers (S1, S2, S3, S4) a corrosion-reducing, in particular zinc-containing, protective layer (S2, S4) each form a lower layer and a tribotechnically active layer (S1, S3) each form an upper layer.

11. Fastening arrangement according to one of claims 1 to 10, characterized in that in a layer system of the first coating (B1) and / or the second coating (B2) with two or more individual layers (S1, S2, S3, S4), the individual layers penetrate each other, preferably in each case up to half the value of their layer thickness (D1, D2, D3, D4).

12. Fastening arrangement according to one of claims 1 to 11, characterized in that the layer thicknesses (DB1, DB2) of the first coating (B1) and / or the second coating (B2) are in the range of 5 to 15 microns.

13. Fastening arrangement according to one of claims 1 to 12, characterized in that the first coating (B1) a specific friction coefficient according to DIN 946 in the range of 0.09 to 0.14 and the second coating (B2) each have a greater coefficient of friction than that first coating (B1), in particular a coefficient of friction of more than 0.15.

14. Fastening arrangement according to one of claims 1 to 13, characterized in that the first coating (B1) contains a dry lubricant, while the second coating (B2) is free of lubricant.

15. Fastening arrangement according to claim 1, wherein the first coating (B1) and / or the second coating (B2) in each case in the salt spray test according to DIN 50021 have values of at least about 600 hours , preferably without red rust formation of 720 hours.

16. The fastening arrangement according to claim 1, wherein the surfaces of the first coating (B1) and the second coating (B2) each have different roughness values.

17. Fastening arrangement according to one of claims 1 to 16, characterized in that the head part (1) consists of a head (1) for torque application and the shaft part (2) of a shaft (2), which together form a screw body (S) form at its free end the threaded portion (3), wherein between the head (1) and the threaded portion (3) on the shaft (2), the disc (4) is rotatably supported and wherein the head (1) and the Disc (4) are each coated with the first and second functional coating (B1, B2).

18. Fastening arrangement according to one of claims 1 to 17, characterized in that the head part (1), in particular the head (1), the shaft part (2), in particular the shaft (2), and the disc (4), which preferably Captive on the shaft part (2) is held, form a combined fastener.

19. Fastening arrangement according to one of claims 1 to 18, dad urch in that the shaft part (2), in particular the shaft (2), with a functional coating (B1) as the head part (1), in particular the head (1), is covered.

20. Fastening arrangement according to one of claims 1 to 16, characterized in that the head part (1) of a nut and the shaft part (2) are formed from a separate shaft, wherein the shaft having an end which the the threaded portion (3) facing free end, with the component form, force and / or cohesively connectable.